Shoe sewing machine



Filed June 15, 1938 5 Sheets-Sheet 1 llllllllkllllll W'iiness July 23, 1940. F. ASHWO RTH SHOE SEWING MACHINE Filed June 15, 1938 3 Sheets-Sheet 2 July 23, 1940. AsHwoR-l-H 2,208,566

' SHOE SEWING MACHINE Filed June 1 .5, 1938 3 Sheets-Sheet 5 Patented July 23, 1940 UNITED STATES PATENT OFFICE SHOE SEWING MACHINE Jersey Application June 15, 1938, Serial No. 2131786 12 Claims.

The present invention relates to lockstitch sewing machines which employ a hook needle to draw loops of needle thread through the work, a loop taker, or shuttle, to carry the loop of needle thread over the locking thread and a takeup to pull the loop of needle thread from the shuttle. The invention is herein illustrated as embodied in. a shoe sewing machine of the McKay type, an example of which is disclosed in the patent to Bernard T. Leveque' No. 1,885,927 issued November 1, 1932, and in the present inventors Patent No. 1,905,031 issued April 25, 1933. It is to be understood, however, that while the invention is particularly applicable to machines of the type disclosed in the I patents referred to certain features of the invention may be used to advantage in other types of hook. needle lockstitch machines.

In the machines of the patents referred to the position of the take-up, uponstopping the machine at the end of the sewing operation, is indeterminate and as a consequence, for reasons which will be hereinafter more fully explained, when the'machine is again started into opera- 5 tion a varying amount of thread is drawn back into the horn by the take-up before the first stitch is formed and tightened in the work. Also before starting the machine an operator often draws some thread from the horn in orderto insure sufiicient needle thread for the first stitch. At the beginning of the seam, therefore, a considerable length of thread is often left projecting from the work inside of the shoe, which not only results in a waste of thread but necessitates an appreciable expenditure of time and labor in trimming off this waste end. v

The principal object of the present invention is to provide a hook needle lockstitch sewing machine with means for preventing the formationv of this waste end of needle thread at the beginning of a seam. I

Other objects are in general to improve the construction and operation of hook needle lockstitch sewing machines and more particularly of patents above referred to.

With the above objects in view, a feature of the invention consists in the provision in a hook needle lockstitch sewing machine, of a normally 'open thread lock arranged between the take-up and the work and actuated upon stopping the machine to clamp the thread at a point along the lead of the thread between the take-up and 5,5 the sewing point and to maintain the thread shoe sewing machines of the type disclosed in th in clamped condition after the machine comes to rest.

In order that the operator may, if necessary, draw ofi an extra length of thread while the machine is at rest, or to enable the machine to berethreaded in case it becomes necessary to replenish the thread, supply, according to another features of the invention, means are provided permitting the operator to release the thread look after the machine has come to a stop.

'Other features of the invention consist in certain devices, construction and combinations of parts hereinafter described and claimed, the advantages of which will be apparent to those skilled in the art from the following description taken in conjunction with the accompanying drawings which illustrate an embodiment of the invention.

In the drawings, Fig. 1 is a View in side elevation of a McKay type lockstitch shoe sewing machine embodying the invention; Fig. 2 is a view in left side elevation of the take-up and thread clamping mechanisms of the machine; Fig. 3 is a view in front elevation of the takeup andthread clamping mechanisms shown in Fig. 2; Fig. 4 is a detail view in side elevation of the supplemental thread lock of the invention; Fig. 5 is a detail plan view, partly in section, of the portion of the supplemental thread lock adjacent the thread clamping jaws, taken along the line 5-5 of Fig. 4; Fig. 6 is a detail plan view similar to Fig. 5, but with the movable jaw assembly omitted; Fig. 7 is a diagrammatic view showing the relative positions of the take-up and the thread locks during the sewing operation when the needle loop is passing over the shuttle, the main thread clamp being in closed position, the supplemental lock open, and the take-up commencing its downward stroke; Fig. 8 is a diagrammatic perspective view showing the needle and loop spreader in stopped position with the thread loop supported for severance by the knife; and Fig. 9 is a diagrammatic view showing the parts in stopped position after the thread has been. cut and the work removed from the machine, with the thread on the work side of the take-up clamped by the supplemental thread lock, and with the main'thread clamp in open position.

Except ashereinafter provided, the machine illustrated in the drawings is of the same construction, arrangement and mode of operation as the machine of Patent No. 1,905,031 abovereferred to. ,The machine comprises a column 12 in the lower portion of whichis mounted an electric motor I4 by which the operating parts of the machine are driven. The main or sewing cam shaft is indicated at I6 and is journalled in the sewing head mounted on the column. The shaft I6 is driven from the motor I4 through a clutch I8, horizontal shaft 26, gear box 22 and vertical shaft 24. The clutch I8 is controlled by means of a foot treadle 26 by means of which the clutch may be actuated to connect and disconnect the shaft 26 from the motor.

The shoe supporting horn, indicated at 28, is provided in its tip with a whirl of usual 'con-- struction, which is driven from the vertical shaft 24 through connections comprising'ahorizontal shaft 36 and a vertical shaft 32 extending upwardly into the base of the "horn,the shaft 32 being hollow to provide a passage 34 for the needle thread to the work. An intermediate bevel gear 36 is provided between shafts 36andh 32 as in Patent No. 1,965,031 hereinafter re-' ferred to.

The stitch forming devices include the straight hook needle, 38, discoidal' shuttle 46, and the loop spreader 42, all actuated from the sewing shaft I6 inthe same manner as in the machine of the prior patent. Connections between the sewing shaft and the needle-comprise a crank pin on the forward end of the sewing shaft, a slotted lever 44 engaged by the, pin, a needle actuating lever 46, a latch 48 connecting the slotted lever and theneedle actuating lever, and a link connecting the needle actuatinglever to the needle bar 56. The shuttle is driven from the needle actuating lever 46 through a link which is connected to a downward extension from the hub of the lever to an upwardly extending arm of the shuttle actuating gear segment 52. This segment meshes with the pinion 54 mounted upon one end of the shaft which drives the shuttle. The loop spreader is likewise actuated from the needle actuating lever 46 throughfthe connections by which the shuttle is actuated, as .described in the aforesaid patent, whereby the loop spreader, duringthe upward stroke of the needle, is caused to engage and spread one side of the needle loop.

Connections are provided from the starting and stopping treadle 26 for actuating the latch 48 to disconnect the needle actuating lever .46 from the sewing shaft I6 when the needle, shuttle and loop spreader are at the limit of their movements in one direction. The parts are thus brought to rest accurately with the needle loop in the hook of the needle and free of the shuttle and with the supply sidev of the needle loop engaged and deflected .by the loop, spreader, the work side of the needle loop being left in posi' tion where it can be readily cut by the operator, as illustrated in Figure 8; These "connections comprise a rod 56 connecting the treadle with an arm 58'fixed on one end of a cross-shaft 66 mounted in. the head of the machine. The arm 58 is provided with a' lug 62 projecting laterally beneath a rearward. extension of an arm '64 loosely mounted upo'n'the cross-shaft and "con nected at its forward end by a link 66 to a rock shaft upon the forward end of which is secured an upwardly extending lever 68 by which the needle may be locked in stopped position-l "A heavy coil spring (not shown) surrounds the cross-shaft 66 and tends to rotate it in a clock wise direction. While the machine is running the treadle 26 is depressed and the lug 62' is held out of engagement with the arm 64. Upon release of the treadle, the clutch I8. is operated to disconnect the motor from the machine and the arm 58 is swung upwardly, causing the lug 62 to engage the rearward extension of the arm 64. Thereafter, the coil spring, acting through the arm 58, turns the arm 64 in a clockwise direction and through the connection to the lever 68, moves the same in a direction to disengage the latch 48 from the needle actuating lever 46 and to lock the needle at the top of its stroke.

a The machine is provided with take-up mechanism similar to that illustrated in Patent No. 1,885,927, said mechanism being actuated from the horizontal shaft 36 by means of a crank pin 'lfllmounted upon a' cam disk 12 secured to the end of the shaft 36. The crank pin I6 is connected by a link I4 to the central pivot I6 of toggle levers 18am]. 86, which are connected, re-

I spectively, to fixed pivot 82 and to one end of the take-up lever 84 pivotally mounted at the lower end of an adjusting lever 86.

The machine is likewise provided with thread clamping mechanism adapted to be actuated in proper timed relation to the other stitch forming devices. 'This mechanism, fully illustrated and described in the aforesaid Patent No. 1,885,927, comprises two. disks illustrated at 88, loosely mounted on a shaft 96 and interposed between an abutment 92 on the machine frame and the hub of a cam lever 64 secured at oneend of the shaft. A cam-faced block 96 is secured to the other end of the shaft, said block being held in engagement with an opposing stationary camfaced block 98 by means of a spring I66. The cam lever 94 is providedwith a cam roll I62 which engages the surface of the cam disk-I2 mounted on the shaft 36. When the cam roll rides onto the high portion of the cam disk I2, the shaft 96 is rocked in a clockwise direction and moved to release the thread clamp to permit thread readily to be drawn. from the supply. When the cam roll reaches the low portion of the cam disk, the shaft 96 is rocked in a counterclockwise direction by the action of the spring I66 and the cam blocks 96 and 98 act to clamp the thread positively.

As hereinbefore described, the machine is stopped with the needle at the top of its stroke and before the shuttle has entered the loop of thread supported by the needle and the loop spreader. Due to the fact that the take-up may continue to oscillate for an appreciable interval after the disconnection from the cam shaft of the sewing devices in the head of the machine, means are provided for holding the thread clamp open during the stopping of the machine and until the machine is again started, inorder that the thread may not be broken bya downward stroke of the take-up. For this purpose the presser foot lifting .mechanism is utilized in a manner fully illustrated and described in Patent No. 1,885,927 above referred to.' Briefly, said mechanism comprises a vertically reciprocating lifting lever I64 and a non-reciprocating retaining lever I66 which are caused to engage successively, when cross-shaft'fill is rocked to stop the machine, an arm secured to a rock shaft I68 to which is attached a lever II6 by which the presser foot is raised. The rocking movement of shaft I68 to raise the presser foot is imparted to the shaft 86 of the thread clamping mechanism by connections comprising an arm II2 pivoted on a bolt H4 in the head of the machine, an adjustable set screw I I6 in said arm adapted 'to be engaged by an arm IIB on shaft I68, and a link I26 connecting arm H2 with the rear end of a lever I22 pivotally mounted on a bolt I24 in the machine frame. The forward end of the lever I22 extends beneath a horizontal arm I26 projecting from the-hub of cam lever 94 on shaft 90 of the thread clamping mechanism so that when the lever I22 is rocked in a counterclockwise direction, as viewed in Figure 2, the shaft 90 of the thread clamp is rotated in a direction to cause the cam-surface blocks 96 and 93 to open the clamp; The opening of the thread clamp by the above described mechanism takes place before the take-up makes its downward stroke in order that the take-up, during such downward stroke, may draw what thread is required through the open clamp from the pply.

The presser foot is 'causedbythe retaining lever I06 to remain in raised position while the machine is at rest and until the machine is again started, and the thread clamp is therefore held open by the lever I22. Upon starting the machine, the clutch I8 is engaged and the. cross shaft BI) rocked in counterclockwise direction to connect the sewing devices in the head of the machine and to move the retaining and lifting levers I06 and I04 respectively to inoperative position. With the lowering of the presser foot, the

lever I22 is permitted to rock in a clockwise di rection, thus restoring the actuation of the thread clamp to the cam disc I2. I

Upon stopping the machine at the completion the shoe is removed from the horn, the friction of the free end of the needle thread in the work may cause thread to be pulled up through the horn. If the take-up has happened to stop at a point above its lower limit of oscillation,*thus leaving slack thread between thesupply and the work, this slack will be drawn up as the shoe is moved away from the horn. 'Il1 certain cases the friction of the thread in the work may be sufficient to cause thread to be drawn off from the supply through the open thread] clamp, after the slack thread has been pulled up, or where no slack thread was present, the take-up having stopped in its down position. Also an operator sometimes makes a practice of pulling off a length of thread from the supply to insure starting a' new seam properly. As a result, a long end of thread is often left projecting from the born. When the machine is put into operation in starting a new seam, this long end of thread is not wholly drawn back, but a considerable portion is left projecting from the inside of the shoe and must be trimmed, wasting both the thread an the operators time. In accordance with the present invention, to prevent this result, there is provided in, the illustrated machine a supplemental normally-open thread lock arranged to clamp the thread at a point along the lead ;of the thread between the take-up and the sewing point, which look is closed upon stopping the machine and is held closed after the machine comes to rest, so asto prevent the withdrawal of thread through the horn from any cause. This supplemental thread lock, best illustrated in Figure 4, comprises a bracket I28 secured at its upper portion by means of machine screws I30 to the machine frame above and forwardly of the take-up mechanism. The bracket is provided with lugs I32 havingrecesses formed therein for the reception of cone-pointed screws by which a cover, not shown, for the take-up mechanism may be pivotally secured to the machine frame. The bracketis likewise provided with a pair of laterally spaced downwardly extending arms I 34, the lower portions of which extend rearwardly beneath the lower end of vertical shaft 32 of the whirl-driving mechanism. Secured to the lower ends of the arms I34 by means of screws I36 is a U-shaped member I38 comprising the fixed jaw of the supplemental thread lock. In order that the thread may be properly guided to the supplemental thread lock from the take-up, a second U-shaped member I40 (see Figure 6) is secured to the bracket arms I34 at right angles to the fixed jaw I38, the member I46 being provided with a vertically-directed aperture I42 in sub stantial alignment with the thread passage 34 in-shaft 32 and with the clamping surface I44 of the fixed jaw I38.

The movable jaw of the supplemental thread lock is indicated at I46, and is yieldingly mounted at the lower end of an arm Hi8 secured by a taper pin IE!) to a horizontal rock shaft I52 journalled in the bracket I28, the arm being arranged to swing between the bracket arms I 34 toward and away from the fixed jaw I38. The yielding mounting for the movable jaw I46 comprises a rod I54 slidably received in the arm, the

jaw I 46 being attached by means of a pin I52 to a lug I58 formed at the inner end of the rod I54. The end of the lug I58 is relieved slightly at its upper, and lower corners IE3 (see Figure 4) to permit a small amount of rocking movement of the jaw M8 about its pivot IEIS, whereby the thread may be gripped with uniform pressure throughout the portion engaged by the jaws when the lock is applied. The rod IE4 is formed adjacent the lug I58 with an enlarged portion I62 which servesas a seat for one end of a compression spring I54 surrounding the rod. The

other endof the spring bearsagaihst the inner face of arm "I48.

The rod is prevented from slipping out of the arm, when the same is swung away to release the look, by a collar or-head I66 secured to the end of the rod outside the arm I48 by means of a pin I68.

To apply the supplemental thread lock upon stopping the machine, the shaft IE2 is rocked in a clockwise direction by connections from the lever I22 by which the main thread clamp is opened during the stopping operation. These connections comprise a rearwardly extending arm I secured to the rock shaft I52 adjacent the outer end thereof and a downwardly extending member I'IZ-ca'rried by the arm lid and having a headed portion I'I I- adapted to bear against the upper side of the forward end of lever I22.

To afford, for a purpose to be described, a yield in the actuating connections for the supplemental thread lock, the member I12 is arranged for vertical sliding movement in the arm III], a relatively stiff compression spring I'It being providedbetween the under side of the arm and the head, portion II l-to transmit the rocking movement from the lever I22 to the arm IIll. Check nuts I18 at the upper end of member I'll. adjustably limit thedownward'extension of the member and thereby permit adjustment of the time of application of the supplemental thread lock relative to the opening of the main thread clamp when the lever I22 is rocked in a counterclockwise direction upon stopping the machine.

To enable the operator to release thesupplemental lock while the machine is at rest, in case it becomes necessary for any reason to draw ofi an extra length of needle thread from the supply, there is provided a handle I80 secured to the outer end of the rock shaft I52. By raising this handle, the arm I48 may be swung outwardly to open the lock, the spring I16 yielding to permit the arm I10 to move relatively to the member I12. Upon release of the handle I80 by the operator, the spring I16 acts upon arm I10 to close the supplemental lock prior tostarting the machine. By requiring the operator to perform the additional act of raising the handle I80 before thread may be drawn ofi manually, waste of thread from this cause is discouraged.

Upon starting the machine, the lever I22 is rocked in clockwise direction, as hereinbefore described, to render operable the main thread clamp, thus simultaneously removing the clamping pressure from the supplemental thread lock. To insure at such times that the thread lock is fully released to remove all resistance to the passage of the thread, a light coil spring I02 surrounds the end of rock shaft I52 and tends to rotate it in counterclockwise direction, as viewed in Fig. 2, one end of the spring engaging the handle I80 while the other end is secured to a lug I84 projecting from the bracket I 28.

Having thus indicated the nature and scope of the invention, and a specific embodiment thereof having been described, what is claimed is:

1. A lockstitch sewing machine having, in combination, stitch forming devices including a hook needle, a loo-p taker and a take-up, a normally open thread lock acting when closed to clamp the needle thread at a point along the lead of the thread between the take-up and the sewing point, and means operating on stopping the machine to close the lock and maintain the lock closed after the machine stops.

2. A lockstitch sewing machine having, in combination, stitch forming devices including a hook needle, a loop taker and a take-up, a normally open thread lock acting when closed to clamp the needle thread at a point along the lead of the thread between the take-up and the sewing point, means for stopping the machine with the take-up in an indeterminate position and with the other stitch forming devices in a position to permit removal of the work and means operating on stopping the machine to close the lock and maintain the lock closed after the machine stops. 3. A lockstitch sewing machine having, in combination, stitch forming devices including a hook needle,',a loop taker and a take-up, a normally open thread lock acting when closed to clamp the needle thread at a point along the lead of the thread between the take-up and the sewing point, means operating on stopping the machine to close the lock and maintain thelock closed after the machine stops, and operating on starting the machine to open the lock. I

4. A lockstitch sewing machine having, in combination, stitch forming devices including a hook needle, a loop taker, and a take-up, means for stopping the machine with certain of the stitch forming devices in predetermined positions while permitting the take-up to coast to an indeterminate stopping position, and a normally inoperative thread lock rendered operative upon stopping the machine to clamp the needle thread at av point along the lead of the thread between the take-up and the sewing point and prevent withdrawal of thread from the machine, after the machine stops.

5. In a lockstitch sewing machine having, in combination, stitch forming devices including a needle, 2. loop taker, and a take-up, mechanism for stopping the machine with certain of the stitch forming devicesin'predetermined positions while permitting the take-up to coast to indeterminate stop position, a thread clamp between the take-up and the supply, means for opening and'closing said thread clamp during each stitch forming cycle, a normally inoperative thread lock arranged to clamp the needle thread at a point along the lead of the thread between the takeup and the sewing point, and means operating upon stopping the machine to close the thread lock and retain said lock closed after the machine stops and simultaneously to open the thread clamp.

6. A lockstitch sewing machine having, in combination, stitch forming devices including a hook needle, a looptaker and take-up, means operative upon stopping the machine to bring the needle to rest at the top of its stroke with the thread loop over the needle while permitting the take-up to coast to an indeterminate stop position, a normally inoperative thread lock, and means operating upon stopping the machine to actuate said thread lock to grip the thread at a point along the lead of the thread between the take-up and the sewing point and to retain the thread in gripped condition afterthe machine is stopped.

7. A lockstitch sewing machine having, in combination, stitch forming devices including a hook needle, a loop taker, and a take-up, means operative upon stopping the machine to bring the needle to rest at the top of its stroke with the thread loop over the needle while permitting the takeup to coast to an indeterminate stopping position, a normally inoperative thread lock, and means operating upon stopping the machine to actuate said thread lock to grip the thread at a point along the lead of the thread between the take-up and the sewing point and upon starting the machine to actuate said thread lock to release the thread. i

8. A lockstitch sewing machine having, in combination, stitch forming devices including a needle, a loop taker, a take-up, and a thread clamp arranged to act on the thread between the takeup and the supply, means operating on stopping the machine to bring the needle to rest in a predetermined position while permitting the take-up to coast to an indeterminate stop position, normally inoperative means rendered active upon stopping the machine to open the thread clamp and to hold the clamp open until the machine is again started, and a thread lock actuated by said normally inoperative means upon stopping the machine to clamp the thread between the take-up and the work and to retain the thread in clamped condition until the said means again becomes inoperative upon starting the machine.

9. A lockstitch shoe sewing machine having, in combination, stitch forming devices including a needle, a loop taker, a take-up and a thread clamp arranged to act on the thread between the take-up and the supply at predetermined times during each stitch forming cycle, mechanism for stopping the machine with the needle and loop taker, in predetermined positions, the take-up being permitted to coast to indeterminate stop position, normally inoperative means rendered active upon stopping the machine to hold open the thread clamp until the machine is again started, a supplemental thread lock arranged between the take-up and the work, and connections from said normally inoperative means for rendering said lock operative only upon stopping the machine and for releasing the look when the machine is again started, said connections including a yielding member to permit the operator to release the lock while the machine is stopped.

10. A lockstitch sewing machine having, in combination, stitch forming devices including a hook needle, a loop taker and a take-up, a normally open thread lock acting when closed to clamp the needle thread between the take-up and the work, and means operating on stopping the machine to close the lock and maintain the lock closed after the machine stops, said means including a yielding member to permit the operator to open the look while the machine is stopped. i

11. A lockstitch shoe sewing machine having, in combination, a shoe supporting horn adapted to extend inside of a shoe, stitch forming devices including a straight hook needle arranged to pass through the sole of a supported shoe into the horn, a loop taker above the horn to take a loop in combination, a shoe supporting horn adapted to extend inside of a shoe, stitch forming devices including a straight hook needle arranged to pass through the sole of a supported shoe into the horn, a loop taker above the horn to take a loop of thread drawn up by the needle, and a take-up to draw thread back into the horn and pull the loop fromthe loop taker, means for stopping the machine with the needle at the top of its stroke with the thread loop over the needle while permitting the take-up to coast to an indeterminate stop position, a normally inoperative thread lock arranged to act on the needle thread at a point along the lead of the thread between the takeup and the sewing point, and means operating upon stopping the machine to actuate the thread lock to prevent withdrawal of thread from the stops.

horn, after the machine FRED ASHWORTH. 

